Visible Spectrum Anti-Reflective Coatings with Reduced Reflections in Ultraviolet and Infrared Spectral Bands

ABSTRACT

Lens coatings and coated lenses which offer full-spectrum protection by reducing back-side reflection of all light spanning from the ultraviolet sub-band B (UVB) to infrared (IR-A) region are provided. The full-spectrum back-side anti-reflective coatings disclosed herein are comprised of multiple thin-film layers of high refractive index (HighIndex) and low refractive index (LowIndex) materials. In many embodiments, the penultimate layer distal from the substrate lens is a HighIndex layer, and the final layer distal from the substrate lens is a LowIndex layer.

RELATED APPLICATIONS

The instant application is a continuation application of U.S.application Ser. No. 14/850,086 filed Sep. 10, 2015, which is acontinuation application of U.S. application Ser. No. 14/189,736 filedFeb. 25, 2014, now U.S. Pat. No. 9,291,746 issued Mar. 22, 2016, thedisclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to lens coatings and coated lenses; andmore particularly coatings and coated lenses that reduce reflectance incertain spectral bands on both sides of the visible spectrum generallyknown to be harmful to eye health.

BACKGROUND OF THE INVENTION

Optical coatings are thin films of material deposited in layers ontolenses for tuning their optical properties, usually light reflectanceand transmission, to suit the lenses' intended purpose. The thicknessand composition of these coatings, amongst other parameters, determinethe resultant physical effects on the lenses' optical profile. In theeyeglass lens industry, optical coatings are applied for purposes suchas anti-reflectance, scratch resistance, high-reflectance in sunglasses,ease of cleaning, anti-fog or other benefits.

A common feature in modern eyeglass lens manufacturing areanti-reflective (AR) coatings. An AR coating is typically achieved viadeposition of thin layers of materials that in combination severelylimit the reflection of visible light off the lens thus increasing thetransmission of visible light through the lens. AR-coated lenses allowapproximately 98% to as much as over 99% transmission of light throughthe lens, whereas some non-AR coated lenses may allow only 92%transmission of light through the lens. These coatings are popularbecause, in addition to improved visible light transmission, they offernumerous other benefits such as decreased surface reflections, glare,and ghost images. Currently, there are several different processes forgenerating lenses with such properties; each of these methods yieldsdistinct physical properties, quality, and longevity of the end product.

SUMMARY OF THE INVENTION

The present invention relates to lens coatings and coated lenses; andmore particularly coatings and coated lenses that reduce reflectance incertain spectral bands on both sides of the visible spectrum generallyknown to be harmful to eye health.

In some embodiments the invention is directed to an anti-reflective (AR)backside coating including:

-   -   a plurality of thin-film layers formed of at least a high        refractive index (HighIndex) material and a low refractive index        (LowIndex) material, wherein the HighIndex material has a        refractive index of at least 1.6 and the LowIndex material has a        refractive index of no greater than 1.5;    -   wherein the thin-films of HighIndex and LowIndex materials that        comprise the AR coating are each at least 1 nm in thickness; and    -   wherein the backside mean UV reflection factor (R_(UV)) of the        coating measured across wavelengths 280-380 nm does not exceed        13% measured at angles of incidence 30° and 45°, and the        backside IR reflection factor (R_(IR)) of the coating measured        across 780-1400 nm does not exceed 14% measured at angles of        incidence 30° or 45°.

In other embodiments the backside mean reflectance factor (R_(m)) of thecoating measured across wavelengths 400-700 nm does not exceed 2.15%. Insome such embodiments the backside mean reflectance factor (R_(m)) ofthe coating measured across wavelengths 400-700 nm does not exceed1.65%. In still other such embodiments the backside mean reflectancefactor (R_(m)) of the coating measured across wavelengths 400-700 nmdoes not exceed 1.15%.

In still other embodiments the backside mean UV reflection factor(R_(UV)) of the coating measured across wavelengths 280-380 nm does notexceed 13% measured at angles of incidence 30° and 45°, and the backsideIR reflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 14% measured at an angle of incidence of 45° or does notexceed 12% measured at an angle of incidence of 30°. In some suchembodiments the backside mean UV reflection factor (R_(UV)) of thecoating measured across wavelengths 280-380 nm does not exceed 13%measured at angles of incidence 30° and 45°, and the backside IRreflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13.5% measured at an angle of incidence of 45° or doesnot exceed 10% measured at an angle of incidence of 30°. In still othersuch embodiments the backside mean UV reflection factor (R_(UV)) of thecoating measured across wavelengths 280-380 nm does not exceed 13%measured at angles of incidence 30° and 45°, and the backside IRreflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13% measured at an angle of incidence of 45° or does notexceed 9.5% measured at an angle of incidence of 30°. In yet other suchembodiments the coating measured across wavelengths 280-380 nm does notexceed 9% measured at angles of incidence 30° and 45°, and the backsideIR reflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 14% measured at angles of incidence 30° or 45°. In stillyet other such embodiments the backside mean UV reflection factor(R_(UV)) of the coating measured across wavelengths 280-380 nm does notexceed 9% measured at angles of incidence 30° and 45°, and the backsideIR reflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13.5% measured at an angle of incidence of 45° or doesnot exceed 12% measured at an angle of incidence of 30°.

In yet other embodiments, the backside mean UV reflection factor(R_(UV)) of the coating measured across wavelengths 280-380 nm does notexceed 5% measured at angles of incidence 30° and 45°.

In still yet other embodiments the layers form a coating stack having aninnermost end configured to be disposed proximal to the backside of asubstrate lens and an outermost end configured to be disposed distal tothe backside of the substrate lens, and wherein the coating stackincludes at least: a final layer formed from a LowIndex material anddisposed at the outermost end; and a penultimate layer formed from aHighIndex material and disposed more proximal than the final layer. Insome such embodiments, the coating includes a top-coat layer disposeddistal to the final LowIndex layer, wherein: the topcoat is comprised ofmaterial selected from one or more of the group consisting of ahydrophobic coat and an oleophobic coat; and the top-coat has athickness of no greater than 20 nm. In other such embodiments the ARcoating further comprises at least one intermediary HighIndex layer andan intermediary LowIndex layer disposed more proximal than thepenultimate layer, and wherein the intermediary HighIndex layer is moreproximal than the intermediary LowIndex layer. In still other suchembodiments the penultimate layer has a thickness of from 55-65 nm, andthe final layer has a thickness of from 97-105 nm, and wherein theintermediary HighIndex layer has a thickness of from 13-15 nm and theintermediary LowIndex layer has a thickness of from 30-36 nm.

In still yet other embodiments, the HighIndex material is a metal oxideselected from the group consisting of oxides of Zr, Ti, Al, Y, Ta, Nd,La, Nb and PrTi or mixtures thereof; and the LowIndex material isselected from the group consisting of SiO2 and mixtures of SiO₂ withalumina.

In still yet other embodiments, the coating further includes one or moreadditional layers, wherein the additional layers are selected from thegroup consisting of a scratch-resistance coating, tinting, polarization,transitions and photochromatic treatment.

In still yet other embodiments, the coating further includes anelectrically conductive layer disposed between the AR coating layershaving a thickness no greater than 15 nm.

In other embodiments the invention is directed to an optical lensincluding:

-   -   a substrate lens having a frontside and a backside;    -   an AR coating disposed one of either adjacent to or distal from        the backside of the substrate lens, the AR coating formed of a        plurality of thin-film layers formed of at least an HighIndex        material and an LowIndex material, wherein the HighIndex        material has a refractive index of at least 1.6 and the LowIndex        material has a refractive index of no greater than 1.5, and        wherein the thin-films of HighIndex and LowIndex materials that        comprise the AR coating are each at least 1 nm in thickness; and    -   wherein the backside mean UV reflection factor (R_(UV)) of the        coating measured across wavelengths 280-380 nm does not exceed        13% measured at angles of incidence 30° and 45°, and the        backside IR reflection factor (R_(IR)) of the coating measured        across 780-1400 nm does not exceed 14% measured at angles of        incidence 30° or 45°.

In other embodiments the lens includes a material selected from thegroup consisting of glass, plastic, poly-carbonate, crown glass,Trivex™, methyl poly(methacrylate), thi(meth)acrylic (co)polymers,polyvinylbutyral, polycarbonates, polyurethanes, poly(thourethanes),polyolallylcarbonate (co)polymers), ethylene/vinyl acetate, polyesters(including PET or PBT), polyepisulfides, polyepoxides,polycarbonate/polyester copolymers, cycloolefin copolymers (includingethylene/norbornene copolymers), high-index materials, and combinationsthereof.

In still other embodiments the backside mean UV reflection factor(R_(UV)) of the coating measured across wavelengths 280-380 nm does notexceed 13% measured at angles of incidence 30° and 45°, and the backsideIR reflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 14% measured at an angle of incidence of 45° or does notexceed 12% measured at an angle of incidence of 30°. In some suchembodiments the backside mean UV reflection factor (R_(UV)) of thecoating measured across wavelengths 280-380 nm does not exceed 13%measured at angles of incidence 30° and 45°, and the backside IRreflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13.5% measured at an angle of incidence of 45° or doesnot exceed 10% measured at an angle of incidence of 30°. In still othersuch embodiments the backside mean UV reflection factor (R_(UV)) of thecoating measured across wavelengths 280-380 nm does not exceed 13%measured at angles of incidence 30° and 45°, and the backside IRreflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13% measured at an angle of incidence of 45° or does notexceed 9.5% measured at an angle of incidence of 30°. In yet other suchembodiments the coating measured across wavelengths 280-380 nm does notexceed 9% measured at angles of incidence 30° and 45°, and the backsideIR reflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 14% measured at angles of incidence 30° or 45°. In stillyet other such embodiments the backside mean UV reflection factor(R_(UV)) of the coating measured across wavelengths 280-380 nm does notexceed 9% measured at angles of incidence 30° and 45°, and the backsideIR reflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13.5% measured at an angle of incidence of 45° or doesnot exceed 12% measured at an angle of incidence of 30°.

In yet other embodiments, the backside mean UV reflection factor(R_(UV)) of the coating measured across wavelengths 280-380 nm does notexceed 5% measured at angles of incidence 30° and 45°.

In still yet other embodiments the backside mean reflectance factor(R_(m)) of the coating measured across wavelengths 400-700 nm does notexceed 2.15%. In some such embodiments the backside mean reflectancefactor (R_(m)) of the coating measured across wavelengths 400-700 nmdoes not exceed 1.65%. In still other such embodiments the backside meanreflectance factor (R_(m)) of the coating measured across wavelengths400-700 nm does not exceed 1.15%.

In still yet other embodiments the lens layers form a coating stackhaving an innermost end configured to be disposed proximal to thebackside of a substrate lens and an outermost end configured to bedisposed distal to the backside of the substrate lens, and wherein thecoating stack including at least: a final layer formed from a LowIndexmaterial and disposed at the outermost end; and a penultimate layerformed from a HighIndex material and disposed more proximal than thefinal layer. In some such embodiments, the lens further includes atop-coat layer disposed distal to the final LowIndex layer, wherein: thetopcoat is comprised of material selected from one or more of the groupconsisting of a hydrophobic coat and an oleophobic coat; and thetop-coat has a thickness of no greater than 20 nm. In still other suchembodiments the AR coating further includes at least one intermediaryHighIndex layer and an intermediary LowIndex layer disposed moreproximal than the penultimate layer, and wherein the intermediaryHighIndex layer is more proximal than the intermediary LowIndex layer.In yet other such embodiments the penultimate layer has a thickness offrom 55-65 nm, and the final layer has a thickness of from 97-105 nm,and wherein the intermediary HighIndex layer has a thickness of from13-15 nm and the intermediary LowIndex layer has a thickness of from30-36 nm.

In still yet other embodiments, the HighIndex material is a metal oxideselected from the group consisting of oxides of Zr, Ti, Al, Y, Ta, Nd,La, Nb and PrTi or mixtures thereof; and the LowIndex material isselected from the group consisting of SiO2 and mixtures of SiO₂ withalumina.

In still yet other embodiments, the coating further includes one or moreadditional layers, wherein the additional layers are selected from thegroup consisting of a scratch-resistance coating, tinting, polarization,transitions and photochromatic treatment.

In still yet other embodiments, the coating further includes anelectrically conductive layer disposed between the AR coating layershaving a thickness no greater than 15 nm.

In still yet other embodiments, the AR coating is disposed on asub-layer of SiO₂ having a thickness of at least 100 nm.

Additional embodiments and features are set forth in part in thedescription that follows, and will become apparent to those skilled inthe art upon examination of the specification or may be learned by thepractice of the disclosed subject matter. A further understanding of thenature and advantages of the present disclosure may be realized byreference to the remaining portions of the specification and data, whichforms a part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The description will be more fully understood with reference to thefollowing figures and data graphs, which are presented as exemplaryembodiments of the invention and should not be construed as a completerecitation of the scope of the invention, wherein:

FIG. 1 provides a schematic demonstrating the back-side reflection oflight from an antireflective-coated ophthalmic lens.

FIG. 2 provides data plots showing the full-spectrum light reflectanceoff the back-side of various lenses with traditional AR coatingsmeasured at 0° angle of incidence.

FIG. 3 provides data plots showing the full-spectrum light reflectanceoff the back-side of various lenses with newer AR coatings measured at0° angle of incidence, these lenses having low UV reflectance but a highIR reflectance.

FIG. 4 provides data plots showing the full-spectrum light reflectanceoff the back-side of a lens in accordance with exemplary embodiments ofthe instant invention measured at 0° angle of incidence.

FIG. 5 provides additional data plots to FIG. 4 showing thefull-spectrum light reflectance off the back-side of a lens inaccordance with another exemplary embodiment of the instant invention atangles of incidence 30° and 45° in addition to 0° angle of incidence.

FIG. 6 provides additional data plots to FIG. 4 showing thefull-spectrum light reflectance off the back-side of a lens inaccordance with another exemplary embodiment of the instant invention atangles of incidence 30° and 45° in addition to 0° angle of incidence.

FIG. 7 provides additional data plots to FIG. 4 showing thefull-spectrum light reflectance off the back-side of a lens inaccordance with another exemplary embodiment of the instant invention atangles of incidence 30° and 45° in addition to 0° angle of incidence.

FIG. 8 provides tables of exemplary coatings in accordance withexemplary embodiments of the instant invention.

Additional embodiments and features are set forth in part in thedescription that follows, and will become apparent to those skilled inthe art upon examination of the specification or may be learned by thepractice of the disclosed subject matter. A further understanding of thenature and advantages of the present disclosure may be realized byreference to the remaining portions of the specification and data, whichforms a part of this disclosure.

DETAILED DISCLOSURE OF THE INVENTION

In accordance with the attached drawings and data, coatings providinglens wearers with full spectrum eye health protection from lightreflected from the back-side of eyeglass lenses are provided. Inembodiments, full spectrum protection, as used herein, refers toreducing the back-side reflectance of all visible incident light similarto conventional AR coatings, while additionally reducing reflectance inthe UV range (UVA and UVB bands), and also in the IR range (IR-A band)when compared to other antireflective coatings. In many embodimentsback-side antireflective (AR) coatings are provided that are comprisedof layered thin films of high refractive index (HighIndex) and lowrefractive index (LowIndex) materials. In some embodiments of theinvention, the HighIndex layers are formed from a ZrO₂ material and theLowIndex layers are formed from a SiO₂ material. Further, embodiments ofthe invention can be combined with other coatings including sub-layers,primer layers, hardcoat layers, anti-static layers, adhesion layers,tint layers, photo-chromic layers, anti-fog layers, etc. In someembodiments, anti-reflection properties are achieved with a typical4-layer combination of HighIndex, LowIndex, HighIndex, LowIndex layerswith the final LowIndex layer furthest from the lens substrate. In manysuch embodiments, the antireflective coating further comprises aplurality of intermediary thin films layers between the substrate lensand the aforementioned AR coating. The intermediary layers between thesubstrate lens and this AR coating may be HighIndex, LowIndex, or otherlens coating materials such as adhesion layers, primer layers,scratch-resistance hard coatings, tinting, polarization, anti-static,transitions or photochromatic treatments. Some embodiments of theinvention may incorporate intermediate layers between the AR stack forsuch benefits as anti-static properties. In some embodiments of theinvention, the final layer on top of the AR stack closest to lens-to-airsurface may be an additional coating material to achieve hydrophobic oroleophobic properties for the final lens. In many embodiments of theinvention, the back-side IR band mean reflectance does not exceed 14%and the back-side UV mean reflectance is no greater than 13%.

INTRODUCTION

The solar spectrum relevant to the current invention consists ofultraviolet radiation (UV), visible light radiation, and infraredradiation (IR). UV radiation spans wavelengths ˜100-380 nanometers (nm),visible light spans ˜380-780 nm, and IR radiation spans ˜780 nm-1 mm.Solar UV radiation is further comprised of three primary subbands: UVC(100-280 nm), UVB (280-315 nm), and UVA (315-380 nm). Similarly, IRradiation is comprised of three main subbands: IR-A (780-1400 nm), IR-B(1400-3000 nm), and IR-C (3000 nm-1 mm).

Eye exposure to UV rays has been shown to cause injury, vision damageand eye disease. UVC rays are the highest energy but since most UVC raysare blocked by Earth's atmosphere, solar UVC does not present a greatthreat to ocular health. Slightly lower in energy, UVB rays can causeerythema, skin cancer and immunosuppression. Finally, UVA rays, closestto the visible light spectrum, are the lowest energy UV rays, and anumber of eye disorders correlate with UVA exposure including cancersand immunosuppression. Other short- and long-term effects of UV exposureinclude: cancer of the eye, eyelid, and surrounding skin; cataracts;pterygium or “surfer's eye,” which affects vision through cornealirritation; and melanoma of the adnexa. (See, e.g., Gallagher R., LeeT., Progress in Biophysics and Molecular Biology 2006, 92, 119-31; andCitek K., Optometry 2008, 79, 143-48, the disclosures of which areincorporated herein by reference.)

Flanking the other end of the visual light spectrum is IR radiation,which can prove just as dangerous to the lens wearer's eyes. Typically,IR waves cause molecular vibrations and rotations and raise thetemperature of the tissues they penetrate; this can result in proteindenaturation. Radiation from the IR-A region presents the most severerisks to ocular health. Almost all IR-A radiation hitting the eye istransmitted through the cornea to the retina. Upon reaching the retina,these waves can cause retinal burns or cataracts. Since the retinaltissues are very difficult to regenerate, retinal burns can result invision loss. (See, e.g., Kourkoumelis N., Tzaphlidou M., ScientificWorld Journal 2011, 11, 520-28, the disclosure of which is incorporatedherein by reference.)

Referring to FIG. 1, ophthalmic lenses (10) can be conveniently dividedinto a front-side (12) (usually convex), and a back-face (14) (usuallyconcave), which is positioned during use closest to the wearer's eye(16). Incoming light (18) is focused through such an ophthalmic lensonto the wearer's eye. As modeled in FIG. 1, a major disadvantage oftraditionally AR coated lenses is that a significant amount ofnon-visible light (20) incident on the back-side of lenses can bereflected (22) directly into the wearer's eyes (16). As discussed above,exposure to this reflected light (particularly UV and IR) can bedetrimental to ocular health.

Adoption of conventional front-side of lens antireflective (AR) coatingsfor use in back-side of lens AR coatings is commonly done, yet it isproblematic. In particular, most conventional front-side AR coatings areformulated primarily to increase light transmission through the lens byreducing visible glare caused by the reflection of visible light (380 to780 nm) from the front-side of the lens, and are not optimized formitigating UV and IR reflections. However, light incident from behindthe wearer, on the back-side of conventionally AR-coated lenses (asdescribed above), will reflect light directly back into the wearer'seyes (see FIG. 1). (See, e.g., Citek K., Optometry 2008, 79, 143-48, thedisclosure of which is incorporated herein by reference.) Thisreflection of light off the back-side of the lens is referred to hereinas back-side reflectance.

To address this issue a number of attempts have been made to form ARcoatings specifically designed for use on the back-side of an ophthalmiclens. However, these attempts have been limited to only portions of thereflected spectrum of light. For example, in some instances, back-sideAR coatings have been formed that attempt to reduce reflections in thevisible region, but have for the most part ignored reflected light inthe UV region, or alternatively, have optimized AR behavior in the UVregion, but only with detrimental consequences to the AR properties ofthe lens in the visible region. (See, e.g., EP 1174734; WO 97/28467, WO2010/125667 and U.S. Pat. No. 4,852,974, the disclosures of each ofwhich are incorporated herein by reference.) Even in those cases wherean attempt has been made to reduce reflection properties in both UV andvisible regions of lens coatings, no attempt has been made to createcoatings capable of providing full-spectrum AR properties, i.e., thatcan provide concurrent AR protection for UV, visible and IR back-sidereflection. (See, e.g., WO 2012/076714.)

FIG. 2 provides the spectral reflectance profile of several lenses withconventional AR coatings, including, Kodak CleaAR™ (lens 3), OptimaResolution Poly™ (lens 5), SEIKO 1.60 Ultra Thin UV™ (lens 7), HoyaHLT150 CR39™ (lens 8), and Crizal FSV Airwear™ (lens 12). As can be seenin the figure, conventional AR coatings have relatively high reflectionin the UV range, good properties in the visible range, and some of whichhave generally low reflections in the IR range. FIG. 3 provides thespectral reflectance profile of the newest generation AR coatingsdesigned to address backside reflection of visible and UV light,including, Crizal UV FSV Orma FIat™ (lens 11) and Crizal UV FSV OrmaFIat™ (lens 14). As can be seen in the figure, newer AR coatings haverelatively low reflection in the UV range, good properties in thevisible range, but have generally higher reflections in the IR range(approaching the higher IR reflection levels of conventional AR coatingsshown in FIG. 2).

The embodiments below provide AR coatings capable of providing fullspectrum protection, that is, reducing the reflectance of all visibleincident light similar to conventional AR coatings, while additionallyreducing reflectance in UVA and UVB bands, and also in the IR-A band forophthalmic lenses.

Full-Spectrum Anti-Reflective Back-Side Lens Coatings

Anti-reflective back-side coatings for ophthalmic lenses allowing forfull spectrum light reflection protection are provided.

Full-spectrum protection, as used herein, refers to the minimization ofreflections from the UVB region through the IR-A band, including thevisible light region in between. Reflectance (R), as used herein, refersto an appropriately computed percentage of light reflected off theback-side of the lens—the side facing the wearer as defined furtherbelow; accordingly, R_(UV) indicates the percentage of back-side UVreflectance, R_(m) and R_(V), indicate the percentage of visible lightreflectance, and R_(IR) indicates the percentage of IR reflectance. Morespecifically:

-   -   R_(m), for the purposes of this disclosure is referred to as the        “mean reflectance” noted (R_(m)), is such as defined in the ISO        13666:2012 Standard, and measured in accordance with the ISO        8980-4 Standard (for an angle of incidence lower than 17°, often        measured at incidence angle of 0° using a contact probe), i.e.        this is the (non weighted) spectral reflection average over the        whole visible spectrum between 400 and 700 nm.    -   R_(V), for the purposes of this disclosure is referred to as the        “luminous reflectance” noted (R_(V)), is such as defined in the        ISO 13666:2012 Standard, and measured in accordance with the ISO        8980-4 Standard (for an angle of incidence lower than 17°, often        measured at incidence angle of 0° using a contact probe), i.e.        this is the weighted spectral reflection average over the whole        visible spectrum between 380 and 780 nm.    -   R_(UV), for the purposes of this disclosure is referred to as        the “mean UV reflection factor”, and is defined as the mean        spectral reflection between 280 and 380 nm. According to the        disclosure, this factor may be measured at an angle of incidence        that may range from 30° to 45°. This UV reflection factor is        defined according to the ISO 13666:2012 Standard. This R_(UV)        may be defined through the following equation:

$\begin{matrix}{R_{UV} = \frac{\int_{280}^{380}{{W(\lambda)}{R(\lambda)}{\partial\lambda}}}{\int_{280}^{380}{{W(\lambda)}{\partial\lambda}}}} & \left( {{EQ}.\mspace{14mu} 1} \right)\end{matrix}$

-   -   where R(λ) represents the lens spectral reflection factor at a        given wavelength, and W(λ) represents a weighting function. This        weighting function is the product of the solar spectrum        irradiance Es(λ), which relates to the relative amounts of        different wavelengths of UVA and UVB rays emitted, and the        efficiency relative spectral function S(λ), which is the        relative damage caused by UVA and UVB rays. The spectral        function W(λ), enabling calculation of the ultraviolet radiation        transmission factors, is defined according to the ISO 13666:2012        Standard. The values for the functions Es(λ) and S(λ) will be        known to those skilled in the art and can be found in ISO        13666:2012 Standard which is incorporated herein by reference.    -   R_(IR), for the purposes of this disclosure is referred to as        the “mean IR reflection factor”, and is defined as the        (non-weighted) spectral reflection average in the IR-A range        (between 780 and 1400 nm). According to the disclosure, this        factor may be measured at an angle of incidence that may range        from 30° to 45° in a manner analogous to those described above.

The full-spectrum anti-reflective back-side coatings of described hereinare provided such that:

-   -   The mean reflectance (Rm) on the rear surface, that is, the (non        weighted) spectral reflection average over the whole visible        spectrum between 400 and 700 nm, is lower than or equal to        2.15%, in other embodiments 1.65%, and in still other        embodiments less than 1.15%.    -   The luminous reflectance (R_(V)) on the rear surface, that is,        the weighted spectral reflection average over the whole visible        spectrum between 380 and 780 nm, is lower than or equal to 2%,        in other embodiments 1.5%, and still other embodiments 1%.    -   The UV reflection factor (R_(UV)) on the rear face, that is the        weighted reflection factor across the wavelength range of        280-380 nm, is lower than or equal to 13% for an angle of        incidence 30° and 45°, and in some embodiments lower than 9%,        and in other embodiments lower than 5%.    -   The IR reflection factor (R_(IR)) on the rear face, that is, the        (non-weighted) spectral reflection average across the wavelength        range of 780-1400 nm, is lower than or equal to 12% for an angle        of incidence 30°, or is lower than or equal to 14% for an angle        of incidence 45° in some embodiments. In other embodiments the        R_(IR) is lower than or equal to 10% for an angle of incidence        30°, or is lower than or equal to 13.5% for an angle of        incidence 45°. And in still other embodiments the R_(IR) is        lower than or equal to 9.5% for an angle of incidence 30°, or is        lower than or equal to 13% for an angle of incidence 45°.

It should be understood that the above values generally describe the“average” or “weighted average” value across the cited range. However,as shown in FIGS. 2 to 7, reflectance within any spectral region, andindeed across the full-spectrum range, is typically described by acurved or undulating line. Accordingly, it will be understood that themajority of the spectral range may fall far below, or far above the“average or weighted average” reflection factors cited above. Inaddition, it will be understood that the extreme low end of the UVspectrum, that is the region of the UVB bordering the UVC spectral range(280-295 nm) may entirely or partially exceed the UV reflection factordescribed above. Similarly, the extreme upper end of the IR spectrum,that is the region bordering 1,400 nm, may entirely or partially exceedthe IR reflection factor described above. It will be understood thatcoatings possessing these outlier reflection factors (within the “borderregions”) are contemplated within the scope of this disclosure.

Turning now to the construction of the coatings, generally the claimedAR back-side coatings are multilayered thin films comprising layers ofhigh refractive index (HighIndex) and low refractive index (LowIndex)materials. Although any number of such HighIndex and LowIndex layers mayform the AR back-side coating, it must include at least three suchlayers. In other embodiments there are at least four such layers, and instill other embodiments there are at least five such layers. Althoughcertain numbers of layers are described herein, it should be understoodthat no maximum or minimum number of layers is proposed.

A high refractive index material (HighIndex) is a material having arefractive index higher than at least 1.6. A low refractive indexmaterial (LowIndex) is a material having a refractive index of no higherthan 1.5. Materials suitable for use in the AR coating embodiments aredescribed as follows:

-   -   HighIndex layers included in embodiments comprise any suitable        coating material having a refractive index of at least 1.6.        Exemplary materials include, one or more oxides of Zr, Ti, Al,        Y, Ta, Nd, La, Nb and PrTi or mixtures thereof, and/or mixtures        and combinations with LowIndex materials so long as the        combination has a refractive index of higher than 1.6. In many        embodiments the HighIndex material is ZrO₂.    -   LowIndex layers included in embodiments comprise any suitable        coating material having a refractive index of no greater than        1.5. Exemplary materials may be comprised of SiO₂ or mixtures of        SiO₂ with other materials such as alumina so long as the        refractive index of the combination is no greater than 1.5.    -   In many embodiments, each HighIndex layer is comprised of ZrO₂        and each LowIndex layer is comprised of SiO₂.

In some embodiments of the invention the AR coating may be disposedalong with other functional coatings and layers, including, for example,primer layers, hardcoat layers, and/or adhesion layers. These layerswould be disposed between the substrate lens and the first back-side ARcoating layer.

It will be understood that the AR back-side coating may, in someembodiments, be deposited on a sub-layer. Such a sub-layer is usuallydeposited to improve the mechanical integrity of the AR coating to thesubstrate (i.e., resistance to damage or debonding) and is notconsidered part of the AR coating stack. This sub-coating may bedeposited directly on the substrate or on top of another coating, suchas those described below. Regardless, the sub-layer, if present, isalways deposited proximal to the substrate in relation to the AR coatingitself. The sub-layer should have a thickness sufficient to ensure thatthe mechanical integrity of the AR coating is improved. In someembodiments this requires a thickness of at least 100 nm, in otherembodiments at least 150 nm. In many embodiments this sub-layercomprises a SiO₂ or doped SiO₂ layer. In addition, such a sub-layer mayitself be formed of multiple layers, including layers directed topreventing reflections between the AR coating and the sub-layer at theinterface thereof. Such multilayer sub-layers will be known to thoseskilled in the art and can be adopted with the AR coatings herein.

The primer layer in some embodiments may be deposited prior to thehardcoat layer. This layer serves to improve the impact resistance ofthe lens and/or the adhesion of the additional coatings to the substratelens. This layer may be comprised of thermoplastic polyurethanesmaterials or combinations thereof. In many embodiments, this layer isbetween 0.2 and 2.5 microns thick.

The hardcoat layer in some embodiments may be an anti-abrasion and/orscratch resistant coating; these may be constructed from either a silaneor acrylate polymers. In order to increase the hardness and/orrefractive index of this hard coating, it may also contain one or moremineral fillers. In many embodiments, this layer may be between 2-10microns thick.

Additionally, other layers of material such as scratch-resistancecoatings, tinting, polarization, transitions and photochromatictreatments to name a few, may be deposited prior to the layers ofHighIndex and LowIndex films comprising back-side coating of the claimeddevice.

Further, an electrically conductive layer may also be deposited in orderto ensure that the lens does not retain or develop a substantial staticcharge. In many embodiments, the electrically conductive layer isincorporated within the AR coating stack, so long as it does not affectthe optical properties of the full-spectrum back-side AR coating. Inorder to ensure that the properties of the AR coating remain untouched,the electrically conductive layer in many embodiments will not exceed athickness of 15 nm. This electrically conductive layer may be comprisedof a metal oxide or doped metal oxide, with the metal being indium, tin,zinc, or mixtures thereof.

Finally, the back-side coating as claimed herein can also be finishedwith an additional, optional hydro- or oleophobic layer. In manyembodiments, this hydrophobic or oleophobic coating is no thicker than20 nm. The optional hydrophobic layer may be comprised of a fluorosilaneor fluoroazane material, with monomers featuring at least twohydrolysable functionalities.

Turning to the construction of the AR coating itself, the coatinggenerally comprises a plurality of layers (each layer being formed ofeither a single material layer or combinations of sub-layers of materialcombined to form a layer) formed of high refractive index materials(HighIndex) and a plurality of layers (each layer being formed of eithera single material layer or combinations of sub-layers of materialscombined to form a layer) formed of low refractive index materials(LowIndex). Each layer of the AR coating has a thickness (expressedherein in nanometers (nm)) of at least 1 nm, such that any layer havingless than this threshold thickness is not included in the count of theHighIndex and LowIndex layers forming the AR back-side coating. In manyembodiments, the HighIndex and LowIndex layers of the AR coatings havethicknesses of at least 10 nm.

It should be understood that the plurality of HighIndex and LowIndexlayers form a sequentially arranged stack that has an innermost end thatis disposed proximal (although not necessarily adjacent to) theback-side of the lens substrate and an outermost end that is disposeddistal to back-side of the lens substrate. The layers that form thestack may be arranged in any order and number so long as the outermostlayers of the AR coating include one each of a HighIndex and LowIndexlayer. In other words, multiple layers of HighIndex materials ormultiple layers of LowIndex materials may be deposited consecutively soas to comprise a single HighIndex or LowIndex layer, respectively.

In some embodiments of the invention, the penultimate layer distal fromthe substrate lens is a HighIndex film comprised in some embodiments ofa zirconia material, and the final layer distal from the substrate lensis a LowIndex film comprised in some embodiments of a silica material.In some embodiments, the final HighIndex layer should be of thicknessfrom 50-70 nm, in other embodiments from 55-65 nm, and in still otherembodiments from 58-65 nm while the final LowIndex layer should be ofthickness from 90-110 nm, and in other embodiments from 97-105 nm, andin still other embodiments from 99-105 nm. The coating may also containa plurality of thin film layers between the substrate lens and thepenultimate HighIndex layer. The plurality of intermediary layersbetween the substrate lens and the aforementioned penultimate HighIndexlayer may be any of the following: the LowIndex materials as describedabove, the HighIndex materials as described above, or any other coatingmaterial such as anti-abrasion coatings, scratch resistance coatings,transitions, photochromatic coatings, tinting, or polarizing coatings.In some embodiments there is at least one additional HighIndex layerbetween the penultimate HighIndex layer and the substrate, formed forexample of zirconia. In many of these embodiments such an intermediaryHighIndex layer may have a thickness of from 10-18 nm, in otherembodiments from 11-16 nm, and in still other embodiments from 13-15 nm.In still other embodiments, there is at least one additional LowIndexlayer between the penultimate layer and the substrate, formed forexample of silica. In many of these embodiments such an intermediaryLowIndex layer may have a thickness of from 25-40 nm, in otherembodiments, from 30-36 nm, and in still other embodiments from 32-35nm.

In other embodiments of the invention, there is a HighIndex layer, and aLowIndex layer, in that order, between the substrate lens and theabove-mentioned penultimate HighIndex layer. This yields a back-side ARcoating comprised of four layers of HighIndex or LowIndex materials inthe following order, starting with the layer most proximal to thesubstrate lens: HighIndex, LowIndex, HighIndex, LowIndex. In many ofthese embodiments, the HighIndex layer more proximal to the substrate isbetween 13-15 nm thick, and the more proximal LowIndex layer is between30-36 nm thick. Additionally, in these embodiments, the penultimateHighIndex layer is between 55-65 nm and the final LowIndex layer isbetween 97-105 nm, as described above. It should be understood that inother embodiments variations of layer thicknesses of the LowIndex andHighIndex material can achieve the same spectral reflectancecharacteristics of the current invention.

Full Spectrum Anti-Reflective Back-side Ophthalmic Lenses

The invention is also related to an ophthalmic article incorporatingthese full spectrum AR back-side coatings.

For the purposes of this invention, the ophthalmic article comprises atleast one lens comprising a substrate material having front and backfaces or sides, where the AR coating is disposed on the back-side of thelens. As defined above, the back-side of the lens references the side ofthe lens or article that is proximal to the wearer's eye when the lensis in use.

With regard to the coating being “disposed on” the substrate, it will beunderstood that this is merely intended to reference that the coating isdeposited above the relevant side or face of the substrate. Further,“disposed on” does not mean that the coating must be in contact with therelevant side or face of the substrate. More specifically, one or moreintermediary coatings may be disposed or arranged between the ARback-side coating and the surface of the substrate.

Substrate materials suitable for use in ophthalmic articles may includeany desirable lens material such as glass, plastic, polymeric,polycarbonate or low-index materials such as crown glass and Trivex™,high-index materials, and combinations thereof. It will be understoodthat the substrate may be formed into any suitable lens type, and mayconform to any shape or outer configuration desired for the particularophthalmic design.

It should be understood that the substrate may include coatings betweenits face or surface and the back-side AR coating. In particular, thesubstrate may be treated with one or more of the following coatings ortreatments: abrasion-resistant layers, scratch-resistant layers,physical or chemical activating treatments, energetic bombardments (suchas ion beam, electron beam, corona discharge, ion spallation,ultraviolet and/or plasma treatment), acid/basic treatments andsolvent-based treatments.

The back-side AR coating may be applied to the substrate using anyconventional means. Generally, one common means of depositing thin-filmlayers onto a substrate lens is using chemical vapor deposition. Thisprocess, which occurs under vacuum, can utilize any one or more of thefollowing methods: electron-beam gun evaporation, thermal evaporation,ion-beam assisted evaporation, ion-beam sputtering, cathode sputtering,plasma-assisted chemical vapor deposition, etc.

It will be further understood that the front face of the optical articlemay be coated or treated with any coating desired, including thosedescribed above, for example, impact resistant layers,abrasion-resistant layers, scratch-resistant layers, polarizing layers,transitions, photochromic layers, tints, hydrophobic layers, oleophobiclayers, anti-fog layers or AR coatings. The AR coatings used for thefront face of the article may be the same as those used on the back-sideor may be different. In particular, these coatings may be designed to beeither of the full spectrum type described herein, or may be designed toprotect against a more limited wavelength range.

EXEMPLARY EMBODIMENTS

FIG. 8 provides the structural and compositional characteristics ofthree exemplary embodiments of the invention. These embodiments are onlyexemplary and illustrative in nature and are not meant to limit thescope of the invention.

In the direction moving distal from the substrate lens surface, onepossible embodiment of the invention is comprised of a 150.0 nm SiO₂sublayer, a HighIndex layer of ZrO₂ 13.9 nm thick, a LowIndex layer ofSiO₂ 32.1 nm thick, the penultimate HighIndex layer of ZrO₂ 64.5 nmthick, and the final LowIndex layer of SiO₂ that is 99.6 nm thick. Thecomposition of this embodiment is shown in FIG. 8, Example 1. Lensescoated with this embodiment of the invention are characterized by thereflectance profile provided in FIG. 5. As demonstrated therein, thisembodiment demonstrates a mean reflection factor R_(UV) of 4.61% between280 and 380 nm at an angle of incidence of 45°, and an R_(UV) of 3.29%at an angle of incidence of 30°. Further, this embodiment ischaracterized by an R_(IR) of 13.17% between 780 and 1400 nm at an angleof incidence of 45°, and an R_(IR) of 9.81% at an angle of incidence of30°. Additionally, this embodiment has an R_(m) value of 1.07% and anR_(V) value of 1.11%.

In the direction moving distal from the substrate lens surface, yetanother embodiment of the invention is comprised of a 150.0 nm SiO₂sublayer, a HighIndex layer of ZrO₂ 14.3 nm thick, a LowIndex layer ofSiO₂ 33.2 nm thick, the penultimate HighIndex layer of ZrO₂ 61.5 nmthick, and the final LowIndex layer of SiO₂ that is 101.9 nm thick. Thecomposition of this embodiment is shown in FIG. 8, Example 2. Lensescoated with this embodiment of the invention are characterized by thereflectance profile provided in FIG. 6. As demonstrated therein, thisembodiment demonstrates a mean reflection factor R_(UV) of 7.41% between280 and 380 nm at an angle of incidence of 45°, and an R_(UV) of 6.83%at an angle of incidence of 30°. Further, this embodiment ischaracterized by an R_(IR) of 13.08% between 780 and 1400 nm at an angleof incidence of 45°, and an R_(IR) of 11.50% at an angle of incidence of30°. Additionally, this embodiment has an R_(m) value of 0.91% and anR_(V) value of 0.86%.

In the direction moving distal from the substrate lens surface, anotherembodiment of the invention is comprised of a 150.0 nm SiO₂ sublayer, aHighIndex layer of ZrO₂ 14.8 nm thick, a LowIndex layer of SiO₂ 34.3 nmthick, the penultimate HighIndex layer of ZrO₂ 58.6 nm thick, and thefinal LowIndex layer of SiO₂ that is 104.3 nm thick. The composition ofthis embodiment is shown in FIG. 8, Example 3. Lenses coated with thisembodiment of the invention are characterized by the reflectance profileprovided in FIG. 7. As demonstrated therein, this embodimentdemonstrates a mean reflection factor R_(UV) of 7.97% between 280 and380 nm at an angle of incidence of 45°, and an R_(UV) of 5.86% at anangle of incidence of 30°. Further, this embodiment is characterized byan R_(IR) that is even lower than the embodiment above, at 12.76%between 780 and 1400 nm at an angle of incidence of 45°, and an R_(IR)of 9.47% at an angle of incidence of 30°. Additionally, this embodimenthas an R_(m) value of 1.06% and an R_(V) value of 0.75%.

DOCTRINE OF EQUIVALENTS

Those skilled in the art will appreciate that the foregoing examples anddescriptions of various preferred embodiments of the present inventionare merely illustrative of the invention as a whole, and that variationsin the steps and various components of the present invention may be madewithin the spirit and scope of the invention. Accordingly, the presentinvention is not limited to the specific embodiments described hereinbut, rather, is defined by the scope of the appended claims.

What is claimed is:
 1. An anti-reflective (AR) backside coatingcomprising: at least three thin-film layers each formed of one of eithera high refractive index (HighIndex) metal oxide material or a lowrefractive index (LowIndex) material, wherein the HighIndex material hasa refractive index of at least 1.6 and the LowIndex material has arefractive index of no greater than 1.5; wherein the thin-film layersform a coating stack disposed atop a backside of a substrate lens, thecoating stack comprising at least a final layer of a LowIndex materialhaving a thickness of from 90-110 nm disposed distal to the backside,and a final layer of a HighIndex material having a thickness of from50-70 nm and disposed distal to the backside; and wherein a backsidemean reflectance factor (R_(m)) of the coating measured acrosswavelengths 400-700 nm does not exceed 2.15%, a backside mean UVreflection factor (R_(UV)) of the coating measured across wavelengths280-380 nm does not exceed 13% measured at angles of incidence 30° and45°, and a backside IR reflection factor (R_(IR)) of the coatingmeasured across 780-1400 nm does not exceed 14% measured at angles ofincidence 30° or 45°.
 2. The coating of claim 1, wherein the coating hasa set of properties selected from the group consisting of: the backsidemean UV reflection factor (R_(UV)) of the coating measured acrosswavelengths 280-380 nm does not exceed 13% measured at angles ofincidence 30° and 45°, and the backside IR reflection factor (R_(IR)) ofthe coating measured across 780-1400 nm does not exceed 14% measured atan angle of incidence of 45° or does not exceed 12% measured at an angleof incidence of 30°; the backside mean UV reflection factor (R_(UV)) ofthe coating measured across wavelengths 280-380 nm does not exceed 13%measured at angles of incidence 30° and 45°, and the backside IRreflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13.5% measured at an angle of incidence of 45° or doesnot exceed 10% measured at an angle of incidence of 30°; the backsidemean UV reflection factor (R_(UV)) of the coating measured acrosswavelengths 280-380 nm does not exceed 13% measured at angles ofincidence 30° and 45°, and the backside IR reflection factor (R_(IR)) ofthe coating measured across 780-1400 nm does not exceed 13% measured atan angle of incidence of 45° or does not exceed 9.5% measured at anangle of incidence of 30°; the backside mean UV reflection factor(R_(UV)) of the coating measured across wavelengths 280-380 nm does notexceed 9% measured at angles of incidence 30° and 45°, and the backsideIR reflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 14% measured at angles of incidence 30° or 45°; thebackside mean UV reflection factor (R_(UV)) of the coating measuredacross wavelengths 280-380 nm does not exceed 9% measured at angles ofincidence 30° and 45°, and the backside IR reflection factor (R_(IR)) ofthe coating measured across 780-1400 nm does not exceed 13.5% measuredat an angle of incidence of 45° or does not exceed 12% measured at anangle of incidence of 30°; the backside mean UV reflection factor(R_(UV)) of the coating measured across wavelengths 280-380 nm does notexceed 5% measured at angles of incidence 30° and 45°; and the backsidemean reflectance factor (R_(m)) of the coating measured acrosswavelengths 400-700 nm does not exceed a value selected from the groupconsisting of 1.65% and 1.15%.
 3. The coating of claim 1, furthercomprising a top-coat layer disposed distal to the final LowIndex layer,wherein: the topcoat is comprised of material selected from one or moreof the group consisting of a hydrophobic coat and an oleophobic coat;and the top-coat has a thickness of no greater than 20 nm.
 4. Thecoating of claim 1, wherein the AR backside coating further comprises atleast one intermediary HighIndex layer and an intermediary LowIndexlayer disposed more proximal than the final layers, and wherein theintermediary HighIndex layer is more proximal than the intermediaryLowIndex layer.
 5. The coating of claim 4, wherein the intermediaryHighIndex layer has a thickness of from 13-15 nm and the intermediaryLowIndex layer has a thickness of from 30-36 nm.
 6. The coating of claim1, wherein: the HighIndex material is a metal oxide selected from thegroup consisting of oxides of Zr, Ti, Al, Y, Ta, Nd, La, Nb and PrTi ormixtures thereof; and the LowIndex material is selected from the groupconsisting of SiO₂ and mixtures of SiO₂ with alumina.
 7. The coating ofclaim 1, further comprising one or more additional layers, wherein theadditional layers are selected from the group consisting of ascratch-resistance coating, tinting, polarization, transitions andphotochromatic treatment.
 8. The coating of claim 1, further comprisingan electrically conductive layer disposed between at least two of thethin-film layers of the AR coating, the electrically conductive layerhaving a thickness no greater than 15 nm.
 9. The coating of claim 1,wherein a backside luminous reflectance factor (R_(V)) of the coatingmeasured across wavelengths 380-780 nm does not exceed 2%.
 10. Thecoating of claim 1, wherein the thickness of the final layer of theHighIndex material is from 58-65 nm, and wherein the thickness of thefinal layer of the LowIndex material is from 99-105 nm.
 11. A method ofcoating and optical lens with an antireflective coating comprising:providing a substrate lens having a frontside and a backside; disposingan antireflective (AR) coating disposed one of either adjacent to ordistal from the backside of the substrate lens, the AR coating formed ofat least three thin-film layers each formed of one of either a highrefractive index (HighIndex) metal oxide material or a low refractiveindex (LowIndex) material, wherein the HighIndex material has arefractive index of at least 1.6 and the LowIndex material has arefractive index of no greater than 1.5; wherein the thin-film layersform a coating stack disposed atop a backside of a substrate lens, thecoating stack comprising at least a final layer of a LowIndex materialhaving a thickness of from 90-110 nm disposed distal to the backside,and a final layer of a HighIndex material having a thickness of from50-70 nm and disposed distal to the backside; and wherein a backsidemean reflectance factor (R_(m)) of the coating measured acrosswavelengths 400-700 nm does not exceed 2.15%, a backside mean UVreflection factor (R_(UV)) of the coating measured across wavelengths280-380 nm does not exceed 13% measured at angles of incidence 30° and45°, and a backside IR reflection factor (R_(IR)) of the coatingmeasured across 780-1400 nm does not exceed 14% measured at angles ofincidence 30° or 45°.
 12. The method of claim 11, wherein the substratelens is comprised of a material selected from the group consisting ofglass, plastic, poly-carbonate, crown glass, Trivex™, methylpoly(methacrylate), thi(meth)acrylic (co)polymers, polyvinylbutyral,polycarbonates, polyurethanes, poly(thourethanes), polyolallylcarbonate(co)polymers), ethylene/vinyl acetate, polyesters (including PET orPBT), polyepisulfides, polyepoxides, polycarbonate/polyester copolymers,cycloolefin copolymers (including ethylene/norbornene copolymers),high-index materials, and combinations thereof.
 13. The method of claim11, wherein the coating has a set of properties selected from the groupconsisting of: the backside mean UV reflection factor (R_(UV)) of thecoating measured across wavelengths 280-380 nm does not exceed 13%measured at angles of incidence 30° and 45°, and the backside IRreflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 14% measured at an angle of incidence of 45° or does notexceed 12% measured at an angle of incidence of 30°; the backside meanUV reflection factor (R_(UV)) of the coating measured across wavelengths280-380 nm does not exceed 13% measured at angles of incidence 30° and45°, and the backside IR reflection factor (R_(IR)) of the coatingmeasured across 780-1400 nm does not exceed 13.5% measured at an angleof incidence of 45° or does not exceed 10% measured at an angle ofincidence of 30°; the backside mean UV reflection factor (R_(UV)) of thecoating measured across wavelengths 280-380 nm does not exceed 13%measured at angles of incidence 30° and 45°, and the backside IRreflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13% measured at an angle of incidence of 45° or does notexceed 9.5% measured at an angle of incidence of 30°; the backside meanUV reflection factor (R_(UV)) of the coating measured across wavelengths280-380 nm does not exceed 9% measured at angles of incidence 30° and45°, and the backside IR reflection factor (R_(IR)) of the coatingmeasured across 780-1400 nm does not exceed 14% measured at angles ofincidence 30° or 45°; the backside mean UV reflection factor (R_(UV)) ofthe coating measured across wavelengths 280-380 nm does not exceed 9%measured at angles of incidence 30° and 45°, and the backside IRreflection factor (R_(IR)) of the coating measured across 780-1400 nmdoes not exceed 13.5% measured at an angle of incidence of 45° or doesnot exceed 12% measured at an angle of incidence of 30°; the backsidemean UV reflection factor (R_(UV)) of the coating measured acrosswavelengths 280-380 nm does not exceed 5% measured at angles ofincidence 30° and 45°; and the backside mean reflectance factor (R_(m))of the coating measured across wavelengths 400-700 nm does not exceed avalue selected from the group consisting of 1.65% and 1.15%.
 14. Themethod of claim 11, further comprising a top-coat layer disposed distalto the final LowIndex layer, wherein: the topcoat is comprised ofmaterial selected from one or more of the group consisting of ahydrophobic coat and an oleophobic coat; and the top-coat has athickness of no greater than 20 nm.
 15. The method of claim 11, whereinthe AR coating further comprises at least one intermediary HighIndexlayer and an intermediary LowIndex layer disposed more proximal than thefinal layers, and wherein the intermediary HighIndex layer is moreproximal than the intermediary LowIndex layer.
 16. The method of claim15, wherein the intermediary HighIndex layer has a thickness of from13-15 nm and the intermediary LowIndex layer has a thickness of from30-36 nm.
 17. The method of claim 11, wherein: the HighIndex material isa metal oxide selected from the group consisting of oxides of Zr, Ti,Al, Y, Ta, Nd, La, Nb and PrTi or mixtures thereof; and the LowIndexmaterial is selected from the group consisting of SiO₂ and mixtures ofSiO₂ with alumina.
 18. The method of claim 11, wherein the AR coating isdisposed on a sub-layer of SiO₂ having a thickness of at least 100 nm.19. The method of claim 11, further comprising one or more additionallayers, wherein the additional layers are selected from the groupconsisting of a scratch-resistance coating, tinting, polarization,transitions and photochromatic treatment.
 20. The method of claim 11,further comprising an electrically conductive layer disposed between atleast two of the thin-film layers of the AR coating, the electricallyconductive layer having a thickness no greater than 15 nm.